With the increase in the amount of transmission information, optical interconnect lines in addition to electrical interconnect lines have been used in recent electronic devices and the like. As an example of such a technique, an opto-electric hybrid board as shown in FIG. 7 has been proposed (see PTL 1, for example). This opto-electric hybrid board includes: a flexible circuit board E1 including an insulative layer 51 made of polyimide and the like, and an electrical interconnect line 52 formed on the front surface of the insulative layer 51; an optical waveguide (optical interconnect line) W1 (including an under cladding layer 56, a core 57 and an over cladding layer 58) made of epoxy resin and the like and stacked on the back surface (surface opposite from the surface with the electrical interconnect line 52 formed thereon) of the insulative layer 51; and an optical element 5 mounted on a predetermined portion (mounting pad 52a) of the electrical interconnect line 52. In this opto-electric hybrid board, both the flexible circuit board E1 and the optical waveguide W1 are flexible. To meet the requirement for the size reduction of recent electronic devices and the like, the opto-electric hybrid board is suitable, for example, for use in a small space when in a bent position and for use in a movable section such as a hinge.